Pre-shaving lotion and method



United States Patent 3,072,536 PRE-SHAVING LOTION AND METHOD David J. Pye, Walnut Creek, Calif.,.assignor to The Dow Chemical. Company, Midland, Mich., a corporationof Delaware No Drawing; Filed-Apr. 8, 1959, Ser. No. 804,861" 4 Glaims. (GI. 167-85) This invention is concernedwith a pre-shaving lotion and with an improved method for shaving.

Ever since man decided that his facial hair should be periodically removed, therev has resulted more or less discomfort particularly forthose men with tough beards and/or tender skins. Numerous devices for removing hair, -as well as some chemical preparations, have been suggested, but the majorityof men still employ razors. When removing hair with a razor, it is customary to apply a soap or grease-composition to the face to facilitate the shaving operation. However, despite the numerous shaving creams and soaps which have been placed on the market over the years, many men still encounter difiiculty in" obtaining a clean, smooth face'without discomfort.

In accordance with the present invention, it has been discovered that the application of a pre-shaving lotion, embodying certain high-molecular-weight, water-soluble polymers, to the skin prior to shaving provides an excellent degree of lubricity to the skin so that the subsequent cutting operation with the razor proceeds more smoothly and with much less discomfort than in previously employed methods of shaving.

The high-molecular-weight, water-soluble polymers employed in the invention include those polymers commonly designated as polyelectrolytes and obtained by vinyl polymerization of monoethylenically unsaturated compounds containing one or more water-solubilizing, carboxyl or carboxamide groups on the molecule. Representative polymers include homopolymers of acrylamide and acrylic acid and copolymers of said compounds with other suitable monomers such as methacrylic acid, methacrylamide and the like. Satisfactory polymers can also be prepared wherein one or more monomers having water solubilizing constituents as set forth above is copolymerized with not more than about 25 mole percent of another vinyl monomer free of water solubilizing groups, such as acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, styrene, alkyl esters of acrylic or methacrylic acid and the like. In any case, it appears that the essential factors for obtaining the desired improvement in lubricity are achieved when the polymer is water-soluble, contains a plurality of carboxyl and/or carboxamide groups and has a molecular weight of at least about 500,000. Preferred polymers are polyacrylamides and copolymers of acrylamide with not more than about 50 mole percent of acrylic acid or an ammonium or alkali metal acrylate. Polymeric compounds similar to the preferred copolymers of acrylamide and acrylates can also be obtained by partial hydrolysis of polyacrylamide with an alkali metal hydroxide.

In carrying out the invention, an aqueous solution containing a small amount of a high-molecular-weight, watersoluble polymer, as set forth above, is applied to the skin and spread to form a film over the area to be shaved. Thereafter shaving with a sharp razor may proceed without further preparation. In a further mode of carrying out the invention, the aqueous solution of high-molecularweight, water-soluble polymer is applied as set forth above and thereafter a shaving soap is applied in conventional fashion prior to the actual shaving operation. In either mode of operation, a high degree of lubricity is afiorded to. the skin and shaving proceeds smoothly and easily with a minimum of irritation.

The amount of polymer to be employed in the presliaving lotion composition'may vary'depending upon the particular polymer employed, the degree of lubricity desired and whether the lotion is employed alone or followed with a conventional shaving cream treatment. In general, the amount of any particular polymer or copolymer required varies in inverse proportion to the molecular weight of said polymer or copolymer. Thus, for example, satisfactory results may be obtained with a preshaving lotion containing about 0.5 percent by weight of a polymerv having a weight-average molecular weight of about 2,000,000 while 2 percent by weight or more of a polymer having a weight-average molecular weight of about 500,000 may be required for equivalent lubricity. In general, the pre-shaving lotion composition should comprise an aqueous solution containing at least about 0.5 percent by weight of polymer and it isgenerally desirable that said solution contain from about 1" to about 4 percent by weight of a polymer. The concentration of polymer is adjusted to provide a lotion composition having a moderately high viscosity so that it may be spread readily on the face without an excessive tendency to run or drip. The amount ofthe lotion compositionemployed will vary depending on the length and density of 'the beard and personal preferences. Good results have been obtained when from about 3 to 10 milliliters of lotion were spread evenly on the area to be shaved.

Various other additaments may be incorporated in the pre-shaving lotion composition as desired. Thus, for example, antiseptics or germicides, such as halogenated methylenebisphenols or long chain quaternary ammonium compounds, cooling agents, such as menthol, and wetting agents may be incorporated in the composition in small amounts. In a preferred composition, a wetting agent such as an alkylaryl sulfonate or an alkylaryl polyoxyalkylene compound is incorporated in the composition in the amount of from about 0.01 to about 1 percent by weight to facilitate spreading of the lotion on oily skin. Other additaments such as perfumes and nontoxic coloring agents can be added as desired.

In a representative operation, a polyacrylamide having a weight-average molecular weight of over 1,000,000 and having about 5 percent of its carboxamide groups by drolyzed to carboxyl groups was dissolved in water together with a commercial wetting agent (Triton X-l00, identified as an alkylaryl polyoxyethylene compound) to produce a solution containing 2 percent by weight of the polyacrylamide and about 0.1 percent by weight of wetting agent. The resulting composition was viscous and spread readily when applied to the skin. Portions of this composition were distributed to a panel of men who applied the material to the face prior to shaving. In several cases, the shaving operation was completed with a safety razor with no further treatment of the face after application of the pro-shave lotion. A majority of the men applied a conventional aerosol or brush-type shaving soap over the pre-shaving lotion and then proceeded to shave with a razor as usual. In a few cases, after the application of the pre-shave lotion, a lather was worked up on the face using a brush and ordinary bar hand soap prior to shaving. In all cases, the panel reported improved smoothness and ease of shaving with a minimum of dragging, nicking and irritation as compared to shaving with a conventional shaving soap without the pre-shaving lotion.

Similarly, improved ease of shaving is obtained by applying pre-shaving lotions consisting of aqueous solutions of the indicated amounts of the following polymers (having molecular weights of over 500,000)

Polymer: Percent by weight Copolymer of equimolar proportions of acrylamide and sodium acrylate 1.0 Copolymer of 85 mole percent of acrylamide and 15 mole percent of methyl methacrylate 1.5 Copolymer of 60 mole percent acrylamide, 30 mole percent ammonium acrylate and mole percent of acrylonitrile 3.5

I claim:

1. A method of shaving which comprises the steps of applying to the face a film of an aqueous solution of a water-soluble, high-molecular-weight polymer, said polymer having a molecular weight of at least about 500,000

and being selected from the group consisting of polyacrylamide, co-polymers of acrylamide with up to about 50 mole percent of acrylic acid, and the ammonium and alkali metal salts of such co-polyrners, and thereafter shaving with a razor.

2. A method according to claim 1 wherein the polymer is employed in the amount of from about 0.5 to 4 percent by weight of the aqueous solution.

3. A method according to claim 1 wherein the solution comprises from about 0.5 to about 4 percent by weight of the polymer and from about 0.01 to about 1 percent by weight of a wetting agent.

4. A pre-shaving lotion composition for application to the skin prior to shaving with a razor which consists essentially of an aqueous solution containing from about 0.5 to about 4 percent by weight of a high-molecularweight, water-soluble polymer and from about 0.01 to about 1 percent by weight of a wetting agent, said polymer having a molecular weight of at least about 500,000 and being selected from the group consisting of polyacrylamide, co-polymers of acrylamide with up to about mole percent of acrylic acid, and the ammonium and alkali metal salts of such co-polymers.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,321 Robson Dec. 31, 1940 2,326,078 Trommsdorlf Aug. 3, 1943 2,754,291 Pollack July 10, 1956 2,798,047 Touey et al July 2, 1957 2,831,841 Jones Apr. 22, 1958 FOREIGN PATENTS 62,708 Netherlands Mar. 15, 1949 703,238 Germany Mar. 4, 1941 731,361 Germany Feb. 8, 1943 796,319 Great Britain June 11, 1958 873,891 Germany Apr. 20, 1953 880,046 Germany July 8, 1949 OTHER REFERENCES Schwartz et al.: Surface Active Agents and Detergents, vol. 11, p. 409, 1958, Interscience Pub.

J. Soc. of Cosmetic Chemists, 8:4, July 1957, pp. 196-211.

Sagarin: Cosmetics Sci. and Tech, Interscience Pub., New York, 1957, pp. 433, 434. 

1. A METHOD OF SHAVING WHICH COMPRISES THE STEPS OF APPLYING TO THE FACE A FILM OF AN AQUEOUS SOLUTION OF A WATER-SOLUBLE, HIGH-MOLECULAR-WEIGHT POLYMER, SAID POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST ABOUT 500,000 AND HAVING SELECTED FROM THE GROUP CONSISTING OF POLYACRYLAMIDE, C0-POLYMERS OF ACRYLAMIDE WITH UP TO ABOUT 50 MOLE PERCENT OF ACRYLIC ACID, AND THE AMMONIUM AND ALKALI METAL SALTS OF SUCH CO-POLYMERS, AND THEREAFTER SHAVING WITH A RAZOR. 